Polymarket bundles certain multi-candidate events as a 'neg-risk' group, which lets you trade all the NO shares as one unit. This strategy buys the NO share of every candidate in the group when their combined cost falls below what the protocol will pay to convert them. You then use Polymarket's NegRiskAdapter contract to merge those NOs into a single guaranteed payout, pocketing the gap between the cheap fragmented NO prices and the fixed conversion value.
Markets on Polymarket where negative-risk conversion arbitrage is the natural play:
